Twindex, or the “Twitter Political Index,” launched yesterday by Twitter, tracks enthusiasm levels for President Obama and Mitt Romney based on an average of 2 million tweets a week that mention the candidates.’

Twindex aims to put figures to just how much Tweeters approve or disprove of the President and Romney on any given day.

According to USA TODAY, Twindex operates “similar to an approval rating from an opinion poll, the daily index runs from zero to 100: a 50 rating is neutral, anything above is positive, below is negative.”

(Twindex) is a new attempt to make sense of the babel of commentary, observation, sarcasm, retweeting, calls to action and linkage that make up the Twitterverse. It is based on a huge “firehose” of data — all 400 million daily tweets — direct from Twitter to its development partner, Topsy Labs, which performs the analysis. That’s a larger pool of data than previous analyses have used. But whether the Twindex can predict election results, reflect broad public opinion or even accurately represent what’s really being said on Twitter isn’t clear based on the current state of social media analysis, say others who have tried to do it.

Still, “Anybody who’s really interested in understanding political dynamics is going to be interested in the ebb and flow of these numbers. They do reflect something about the tone and intensity of the political conversation that is going on in this country,” says Democratic pollster Mark Mellman, who helped Twitter develop the index.

Since the 2008 presidential election Twitter has exploded with political tweeting. Both the President and Romney have taken the heated campaign to Twitter.

Perhaps reflecting the negativity of much of the presidential campaigns’ advertising and rhetoric, both candidates have stayed almost entirely in negative territory, below a neutral 50, rating since May 1, when Twitter began compiling the daily index . Obama hit a high of 74 on May 9, the day he endorsed same-sex marriage, and Romney reached 63 on June 5, when Wisconsin’s Republican governor withstood a recall election.

So far, the index has generally correlated with both Gallup approval rating polls and the RealClearPolitics polling average, Sharp says. But the index is not a substitute for polling, he adds, likening it to a “barometer” of political opinion rather than the “thermometer” that polls provide.

“This is not an alternative, it’s not a replacement for opinion polls. It’s a new sort of information that there was no way of accessing,” says Rishab Ghosh, Topsy’s chief scientist. “We aren’t asking anybody anything. People are saying things on their own.”

The Twitterverse isn’t particularly politically biased, say the Republican and Democratic pollsters worked on the project, because while Twitter users overall may be younger and therefore more likely to support Obama, conservative tweeters tend to be more active.

“We were surprised. … It’s not a super Democratic skew,” says Jon McHenry of North Star Opinion Research, a Republican polling firm that partnered with Twitter in designing the index. When the Obama campaign introduces a new hashtag, or topic, “conservatives tend to hijack it almost instantly.”

Twindex relies on “sentiment analysis,” a way of determining Twitter users’ attitudes by social media posts. According to Topsy Labs, Twitter’s development partner and Twindex analysis performer, the system can identify positive or negative tweets, interpret sarcasm and humor and even figure out location of the Tweeter based on their social media posts. Twitter’s advantage to more accurate “sentiment analysis” is the vast amount of data available, an archive of billions of tweets.

Pollsters are very interested in social media analysis because of the volume of opinions expressed, says Frank Newport, editor in chief of the Gallup Poll. “It would be foolish not to examine the value of these millions of opinions. But there’s a big ‘but,’ ” he cautioned. Twitter users, 140 million worldwide, aren’t a representative sample of the general population — for instance, they tend to be younger and, obviously, more technologically savvy. “My concern is, who are these people?” Newport says. As a result, “I don’t think anyone has figured out whether it’s truly useful.’’

In other words, if a Twitter analysis can’t predict who is going to win the election, what’s the point?

Social media like Twitter and Facebook “is where public discussions take place in new and powerful ways. But those conversations are not necessarily predictive of specific outcomes like elections, revolutions, or successful products,” says Marc Smith, founder of the Social Media Research Foundation. Like sending a photographer to shoot pictures of a crowd at a political rally, “descriptions of social media discussion spaces can be important news,” Smith says. “But we do not usually ask crowd photos to predict outcomes, even when they are newsworthy.”